Temperature Dependent Electrical Properties and Catalytic Activities of\({\text{La}}_{\text{2}}{\text{O}}_{\text{3}}\text{–}{\text{CO}}_{\text{2}}\text{–}{\text{H}}_{\text{2}}\text{O}\)Phase System

Abstract

We present a study of electrical properties and catalytic activities of materials belonging to the hydrated carbonated system ${\text{La}}_2{\text{O}}_3\text{–}{\text{CO}}_2\text{–}{\text{H}}_2\text{O}$. The polycrystalline hydroxycarbonate, dioxycarbonate, and oxide are prepared via a coprecipitation route followed by heat treatment. The electrical conduction of the phases obtained by thermal decomposition from ${\text{LaOHCO}}_3$, ${\text{H}}_2\text{O}$is analyzed by electrical impedance spectroscopy, from ${25}^{°}\text{C}$to ${950}^{°}\text{C}$, under air. The catalytic properties of ${\text{LaOHCO}}_3$, ${\text{La}}_2{\text{O}}_2{\text{CO}}_3$and ${\text{La}}_2{\text{O}}_3$polycrystalline phases are studied by FTIR spectroscopy, in presence of gas mixtures CO-air and ${\text{CH}}_4$-air, at temperatures ranging between ${100}^{°}\text{C}$to ${525}^{°}\text{C}$. The three materials behave differently in presence of CO or ${\text{CH}}_4$gases.